Electrical insulation tube

Abstract

An electrical insulating tube is provided which isolates at least one conductor placed within the tube and a second conductor or elements that are placed outside the tube. The tube comprises a first conductive coating or foil placed on the inner surface or within the insulating tube material but substantially near its inner surface with this first conductive coating or foil electrically referenced to the conductor placed within the tube. The tube optionally comprises a second conductive coating or foil placed on the outer surface or within the tube material but substantially near its outside surface with this second conductive coating or foil electrically referenced to a conductor or electrical element placed outside the tube. Several embodiments and methods to make the tube are described.

What is claimed is: 
     
         1 . An electrically insulating tube made by rolling a sheet,
 wherein the sheet comprises electrically insulating material, and   wherein a conductive or semiconductive coating or foil is placed on a portion of the sheet at or substantially near an edge of the sheet prior to rolling, and   wherein the rolling of the sheet is initiated at the said edge of the sheet such that the conductive or semiconductive coating or foil is positioned on the inner surface or substantially near the inner surface of the said tube.   
     
     
         2 . The electrically insulating tube of  claim 1 ,
 wherein the conductive or semiconductive coating or foil positioned on the inner surface or substantially near the inner surface of the tube is electrically connected or referenced to an electrical conductor positioned inside the tube thus placing the said conductive or semiconductive coating or foil at substantially the same electric potential as the said conductor.   
     
     
         3 . The electrically insulating tube of  claim 1 ,
 wherein a second conductive or semiconductive coating or foil is placed on a portion of the sheet at or substantially near an edge of the sheet where the rolling of the sheet is completed, such that the said second conductive or semiconductive coating or foil is positioned on the outer surface or substantially near the outer surface of the said tube.   
     
     
         4 . The electrically insulating tube of  claim 3 ,
 wherein the said second conductive or semiconductive coating or foil positioned on the outer surface or substantially near the outer surface of the tube is electrically connected or referenced to an electrical conductor positioned outside the tube thus placing the said coating or foil at substantially the same electric potential as the said conductor.   
     
     
         5 . An electrically insulating tube made by rolling a sheet of electrically insulating material,
 wherein at least one of the two surfaces of the sheet is coated with a semiconductive material or foil, and   wherein the semiconductive material or foil on or near the inner surface of the tube is electrically connected or referenced to an electrical conductor positioned inside the tube thus placing the said coating or foil on the inner surface at substantially the same electric potential as the said conductor inside the tube, and   wherein the coating or foil at or near the outer surface of the tube is electrically connected or referenced to an electrical conductor positioned outside the tube thus placing the said coating or foil on the outer surface at substantially the same electric potential as the said conductor outside the tube.   
     
     
         6 . The electrically insulating tube of  claim 1 ,
 wherein the insulating tube separates a first electrical winding or conductor placed within the tube from a second electrical winding or conductor placed outside the tube.   
     
     
         7 . The electrically insulating tube of  claim 5 ,
 wherein the insulating tube separates a first electrical winding or conductor placed within the tube from a second electrical winding or conductor placed outside the tube.